<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
       body>div{
         width: 200px;
         /*height: 200px;*/
         border: 1px solid red;
         /*当元素的所有子元素全部浮动时，自动识别的高度为0，后面的元素会顶上来导致显示一沉，
         添加overflow：hidden解决此异常*/
         overflow: hidden;
       }
       #d1{
         width: 80px;
         height: 60px;
         background-color: red;
         float: left;
       }
       #d2{
         width: 80px;
         height: 50px;
         background-color: green;
         float: left;
       }
       #d3{
         width: 80px;
         height: 50px;
         background-color: blue;
         float: left;
       }
    </style>
</head>
<body>
<div>
  <div id="d1"></div>
  <div id="d2"></div>
  <div id="d3"></div>
</div>
</body>
</html>